1. Field of the Invention
This invention relates to a system for producing electrical energy, particularly with the use of solar heat as the prime energy source.
2. Description of the Prior Art
The patent literature is replete with systems utilizing wind, waves, and solar heat as energy sources for generating electrical power. The main sources of electrical power in the world today are hydroelectric systems and fossil fuel powered generating systems. The next most significant source of electrical power is nuclear powered generators.
As far as hydroelectric power is concerned, the power generators must be reasonably close to their ultimate market and the heavily populated and industrialized sections of the world are fast using up all available new sources of hydropower. The systems powered by fossil fuels such as coal, gas and oil have the problem that these fuels are now becoming in short supply and also are becoming extremely expensive. Also, fossil fuels are environmentally objectionable, since these contribute to global warming and also contaminate the atmosphere by leaving poisonous residues not only in the air, but also often in many effluents. The nuclear systems are not only very expensive in terms of construction costs but they also have the problem of requiring extensive safety systems to protect against the radiation in the plant itself. Moreover, there is also the major problem of safely disposing of the highly dangerous wastes.
Because of these problems with the traditional systems, there has been a greatly increased interest in solar energy as a major energy source. Various systems have been proposed involving the use of solar energy for generating electrical power and some such systems have recently been developed for space vehicles; see, for instance, Canadian Patent No. 718,175, issued Sep. 21, 1965. That system uses a solar energy absorber for heating a liquid which vaporizes to drive a turbine which in turn drives a generator. Such a system with its vaporizing and condensing systems is obviously practical only for very small systems such as would be used in space crafts.
There are many patents in existence which describe the use of wind power for driving electrical generators and one quite recent form of wind turbine generator is that described in U.S. Pat. No. 3,720,840 issued Mar. 14, 1973. In Goodman, U.S. Pat. No. 3,048,066, a vertical stack arrangement is described having a series of fans driven by solar created thermal currents, with the fans being capable of driving electric generators.
The failure of ground level solar energy collectors in the past has been related to an inadequate collection area. Thus, it is known that for a sunny region such as Texas, an average heat absorption of an optimally tilted collector is about 0.45 kw/m.sup.2 as a year round average sunny, daylight hours. On this basis it has been estimated that a collector area of 37 square miles would be required for a 1000 mw power plant.
Of course, it is highly desirable to have these plants close to major population areas and in these areas land is at a premium. One design of solar power plant capable of greatly decreasing the land area requirements for a given amount of power production is that described in Drucker, U.S. Pat. No. 3,979,597, issued Sep. 7, 1976. A further improvement to that solar power plant is described in Drucker, U.S. Pat. No. 5,694,774.
It is the object of the present invention to further improve the efficiency of the power plant of U.S. Pat. No. 5,694,774.